The term 'SERVES TO RESERVE' can be broken down into two four-letter words, 'SERVES' and 'LETS'. The word 'SERVES' is a verb meaning to provide a service or to work for someone. It can also mean to offer something to someone. The word 'LETS' is a verb meaning to allow or to permit. Together, the phrase 'SERVES TO RESERVE' can be interpreted as providing a service in order to keep something reserved or to maintain control over it.